State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China.
Environ Sci Technol. 2022 Feb 1;56(3):1917-1926. doi: 10.1021/acs.est.1c06068. Epub 2021 Dec 2.
In real-world application, Cu/SSZ-13 simultaneously suffers severe deactivation from hydrothermal aging and SO poisoning during the periodic regeneration of diesel particulate filter (DPF). Herein, we first investigated the synergistic deactivation mechanism of hydrothermal aging and SO poisoning on Cu/SSZ-13 under SCR condition. Hydrothermal aging alone induces more severe degradation of selective catalytic reduction (SCR) performance than SO poisoning alone, while the presence of SO during hydrothermal aging causes further worse SCR performance compared with hydrothermal aging alone. Hydrothermal aging not only damages Si-OH-Al sites, particularly in four-membered ring (4MR) of the CHA cage, but also brings the conversion of ZCuOH, leading to the formation of inactive CuO/CuAlO species. By contrast, SO poisoning alone is more prone to promote the transformation of ZCuOH to ZCu. Synergistic deactivation of hydrothermal aging and SO poisoning would exacerbate the damage of Si-OH-Al sites and then the formation of CuO/CuAlO species. These results are expected to assist the knowledge-based catalyst design for diesel aftertreatment applications.
在实际应用中，Cu/SSZ-13 在柴油颗粒过滤器（DPF）的周期性再生过程中，同时遭受水热老化和 SO 中毒的严重失活。在此，我们首先研究了水热老化和 SO 中毒在 SCR 条件下对 Cu/SSZ-13 的协同失活机制。水热老化单独作用比 SO 中毒单独作用更严重地降低了选择性催化还原（SCR）性能，而在水热老化过程中存在 SO 会导致比单独水热老化更差的 SCR 性能。水热老化不仅会破坏 Si-OH-Al 位，特别是 CHA 笼中的四元环（4MR），还会导致 ZCuOH 的转化，形成无活性的 CuO/CuAlO 物种。相比之下，SO 中毒单独作用更容易促进 ZCuOH 向 ZCu 的转化。水热老化和 SO 中毒的协同失活会加剧 Si-OH-Al 位的破坏，然后形成 CuO/CuAlO 物种。这些结果有望为柴油后处理应用中的催化剂设计提供理论支持。
